The game has only one rule, and it’s a simple one: Don’t think about white bears. You can think about anything else, but you can’t think about that. Ready? Close your eyes, take a deep breath, and banish the animals from your head.

You just lost the game. Everyone loses the game. As Dostoevsky observed in Winter Notes on Summer Impressions: “Try to avoid thinking of a white bear, and you will see that the cursed thing will come to mind every minute.” In fact, whenever we try not to think about something, be it a white bear or the marshmallow man, that something gets trapped in the mind, stuck in the recursive loop of self-consciousness. Our attempt at repression turns into an odd fixation.

This human frailty has profound consequences. Dan Wegner, a psychologist at Harvard, refers to the failure as an “ironic” mental process. Whenever we establish a mental goal — such as trying not to think about white bears — the goal is accompanied by an inevitable follow-up thought, as the brain checks to see if we’re making progress. The end result, of course, is that we obsess over the one thing we’re trying to avoid. Wegner argues that this twitch is responsible for all sorts of afflictions, from anxiety disorder (we get anxious whenever we think about not getting anxious) to insomnia, which can occur when the drowsy brain checks to see if we’ve fallen asleep (and so we wake up).

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Although these perverse thoughts can be irritating — wouldn’t it be nice to be able to fall asleep at will, like a cat? — they also reveal an essential feature of the human mind, which is that it doesn’t just think. It constantly thinks about how it thinks. We’re insufferably self-aware, like some post-modern novel, so that the brain can’t go for more than a few seconds before it starts calling attention to itself, reflecting on its own contents, thoughts, and feelings. This even applies to thoughts we’re trying to avoid, which is why those white bears are so inescapable.

The technical term for this is “metacognition,” and it’s a rather surreal skill. Imagine that M.C. Escher drawing of a hand drawing a hand, or a video camera making a movie of itself. The cortex is the same way, as it constantly transforms the subject at the center of consciousness — you — into yet another object contemplated by consciousness. Of course, like all things meta, the process can quickly spiral out of control. When a mind thinks about metacognition, it’s thinking about how it thinks about how it thinks. And so on.

But metacognition isn’t just a quirk of consciousness: It also has immense practical value, which scientists are only beginning to fully grasp. As the world confronts a series of epic problems, from global warming to the financial crisis, world leaders (including the new American president) will be making a slew of difficult decisions. In addition to weighing their myriad policy options, they could find that reflecting on the decision-making process itself proves an extremely powerful tool. How we decide is normally described in binary terms: There’s rational deliberation or gut instinct, Apollonian logic versus Dionysian feeling, the reptilian brain fighting the frontal lobes. Human nature is reduced to an either/or situation. In recent years, however, scientists have begun to discover that while both of these approaches have distinct advantages, they also have many shortcomings. There is no universal solution to the problem of decision making, for the real world is just too complex. In fact, many scientists now argue that the best predictor of good judgment isn’t intuition or intelligence or even experience. Rather, it’s the willingness to engage in introspection, to cultivate what Philip Tetlock, a psychologist at the University of California, Berkeley, calls “the art of self-overhearing.” The mind that thinks about itself thinks better.

The modern story of metacognition begins with a coin toss. In the early 1970s, Daniel Kahneman and Amos Tversky, psychologists at Hebrew University, began to conduct a series of experiments that revolved around hypothetical gambles. Let’s say, for instance, that I offer you a simple wager. If a coin lands on heads, I’ll pay you $1. If, however, it comes up tails, you’ll owe me only 75 cents. A perfectly rational person would always take the gamble since, over the long term, they’ll come out way ahead. But that isn’t what happens. The psychologists noticed that when people were given the opportunity to gamble $1 based on a coin toss, they demanded that their opponent gamble $2. In other words, the pain of a loss was approximately twice as potent as the pleasure generated by a gain. This emotional asymmetry, known as loss aversion, leads people to make all sorts of silly decisions. In recent years the psychological phenomenon has been blamed for everything from bad investment decisions — it reduces the stock market return of the average active trader by 3.4 percent — to the failed Iraq policy of the Bush administration.